[S390] cio: commit all pmcw changes.

Sometimes we change the pmcw configuration but don't call msch
to transmit these changes to the channel subsystem.

The patch fixes this by calling cio_commit_config in such cases.

Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>